This is NOT An Upgrade to UU1.0 or UU1.5, you MUST start with a Fresh Clean unmodded Legacy install. If you try installing over UU1.0 or 1.5 you will CERTAINLY have problems!
This is part 1 of a 2 part installer. Be sure to grab Part 2 of 2 as well, both are required!.
UU2.0 is a FULL INSTALL.

Now that's out of the way. You will find a new menu structure, more
races, enhanced missions, the new Vs Armada, and Instant Vs modes. As
well as the new "Exploring History" mode which is a mostly non combat
mode that explores Earth and Mars development from the NX-01's time to
the Ncc-1701F.

Great new intro, loading screens and main menu
graphic by Mindwipe. Three interviews with the CoWriter of the Stock
Campaign Derek Chester sone by Mindwipe himself and a TMP Theme music
vid with Mike Shaw. Rebuilt mainmenu by Muldrf. Enhanced Explosions and
weapon effects by Miri as well as some nice new Glow work on some of
our favorite starships. New Terran Empire ships by Nix and new Section
31 by Gan as well as some other offerings. Additional ships by Maxloef.
New Map Editor menu structure with easier navigation setup by Tjoz with
nearly all flyable 2.0 ships as well as the stock components. A fair
number of ships by MRJohn have been added. And lets certainly not
forget DJ Curtis's beautiful Century and Vivace Class starships.
Enhanced UUTools utility and the new LMTools Modding Utilties have been
released as well, also the Legacymissioneditor is included although the
LMTools has full mission building abilities built in. I have included
the Modinstaller for good measure for any aspiring modders out there
who might find use for it.

You most likely have only installed one half of the mod to the proper directory. Install Both parts of the mod to your Legacy directory. If you have a 64bit OS it will try to install the one half to the x86 Program Files directory. If you are rrunning on a 32 bit OS you will not have that issue.